AudioTrack and AudioRecord: getNotificationPeriodInFrames()

This is needed for AAudioStream_getFramesPerBurst(),
which is needed for callbacks to work correctly.

Bug: 34716038
Bug: 36489240
Test: CTS test_aaudio.cpp
Change-Id: I0e3f3f18a22bf6da8c288f0d2caec0bff0153f2f
Signed-off-by: Phil Burk <philburk@google.com>
diff --git a/media/libaudioclient/include/AudioTrack.h b/media/libaudioclient/include/AudioTrack.h
index 0358363..16eb225 100644
--- a/media/libaudioclient/include/AudioTrack.h
+++ b/media/libaudioclient/include/AudioTrack.h
@@ -348,7 +348,12 @@
             uint32_t    channelCount() const { return mChannelCount; }
             size_t      frameCount() const  { return mFrameCount; }
 
-    // TODO consider notificationFrames() if needed
+    /*
+     * Return the period of the notification callback in frames.
+     * This value is set when the AudioTrack is constructed.
+     * It can be modified if the AudioTrack is rerouted.
+     */
+            uint32_t    getNotificationPeriodInFrames() const { return mNotificationFramesAct; }
 
     /* Return effective size of audio buffer that an application writes to
      * or a negative error if the track is uninitialized.